Being overweight or seriously underweight as a teenager curbs life expectancy as much as smoking 10 cigarettes a day, a study suggests.\nSwedish researchers followed 46,000 men from the age of 18 for 38 years.

Vitamin D protects bone, preserves muscle strength, and regulates cell growth and energy metabolism. It also offers some protection against cancer and other disease, but are these effects really important for health and life expectancy? The answer seems to be a resounding yes.